Multifocal Uremic Tumoral Calcinosis From Prolonged Hyperparathyroidism in Autosomal Dominant Polycystic Kidney Disease.

Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease. Prolonged stimulation of the parathyroid glands can lead to severe mineral bone disorders. Uremic tumoral calcinosis (UTC) is a rare but debilitating manifestation of prolonged hyperparathyroidism characterized by periarticular calcium-phosphate deposits. This case describes the progression of SHPT to multifocal UTC in a patient with autosomal dominant polycystic kidney disease (ADPKD). A 46-year-old female with ADPKD-related end-stage renal disease (ESRD) was evaluated for renal transplantation and found to have an elevated parathyroid hormone (PTH) level. A sestamibi scan revealed a left inferior pole parathyroid adenoma, and she underwent a targeted parathyroidectomy. The remaining glands appeared normal intraoperatively and were preserved. Despite optimal medical management after parathyroidectomy, the patient's PTH levels remained markedly elevated. In the ensuing year, the patient developed complications from prolonged hyperparathyroidism, including severe bone pain, arthralgias, pathologic fractures, and multifocal UTC. In ESRD, impaired phosphate excretion and vitamin D metabolism disrupt calcium-phosphate homeostasis, altering the feedback to the parathyroid glands. This leads to chronic elevation of PTH and promotes bone resorption, increasing the risk of pathologic fractures. In some cases, ectopic calcification may occur. Multifocal UTC reflects a severe manifestation of these systemic mineral imbalances. This case illustrates a rare but severe complication of chronic hyperparathyroidism in the setting of ADPKD, where refractory SHPT progressed to multifocal UTC despite surgical and medical interventions. Early recognition and aggressive, multidisciplinary management are critical to mitigate the progression of this condition and preserve quality of life.